Sheffield heatwave: 'Risk to life' alert issued over dozens spotted swimming in Damflask Reservoir beauty spot

Dozens of people have been taking a dip in Damflask Reservoir this week as temperatures in Sheffield hit a record high of 39.4C on Tuesday afternoon.

Some groups have even been seen swimming right into the middle of the body of water – which is 27m deep – or using inflatables to float on the surface.

But Yorkshire Water, which manages and maintains the Loxley Valley beauty spot, has warned people not to swim there as there are a number of hidden dangers that could lead them to get into difficulty in the water.

The warning comes after 11 people died in open water in the UK since the heatwave began on July 9.

A spokesperson for Yorkshire Water said: “Swimming is not permitted at our sites as there are several risks associated with open water at reservoirs, which are often underestimated, that pose a potential risk to life.

"These include cold water shock, unseen objects under the water, the hazards of operational machinery and the underwater currents they can cause.

"Tragically we have already seen a number of open water deaths around the country, including in our region this summer, and it is important people do not take the risk to enter our reservoirs at any time.”

They added: “Despite signage being in place expressly prohibiting swimming in our reservoirs, we are also employing marshals at some sites to keep people safe and to reinforce the no swimming policy.

"We would urge visitors to our sites not to enter the water under any circumstances and if they see someone in trouble to contact the fire service by dialling 999."

A number of young people have died in South Yorkshire’s open waters over the years – the most recent being Sam Haycock, who drowned aged just 16 in Rotherham’s Ulley Reservoir last year.

A few weeks ago Sam’s father Simon urged people to refrain from entering open water.

He said: “Don’t be tempted to go in and cool off. They’re not the right places to be doing that.

“You can’t see the temperature of the water, you can’t see the undercurrent. It is quite possible you could get into trouble.”